Invasive candidiasis (IC) is one of the most serious threats to patients in a critical setting. With as many as 60,000 cases per year in the U.S., the total cost associated with IC in the U.S. may be as high as $2-4 billion/year. One of the most critical factors influencing patient outcome is early diagnosis. The goal of this project is a rapi and inexpensive immunoassay that will use serum as a sample to identify the presence of IC. This is an unmet need for diagnosis of candidiasis, particularly for tests near the point of patien care. The target population will be individuals for whom advanced medical intervention and use of potent cytotoxic drugs have led to a proliferation of deep-seated infection by Candida spp. The overall hypothesis is that protein antigens of Candida spp. are shed into blood in concentrations that would be biomarkers for disease. The approach will be immunoassay for the presence of two or more distinct antigens that i) are shared across Candida spp. that cause IC and ii) are shed into blood during infection. Simultaneous detection of multiple antigens will markedly enhance the predictive value. The product will be assays with the lateral flow immunoassay (LFI) and/or enzyme-linked immunoassay (ELISA) platforms. To date, we have used a novel biomarker discover process termed In vivo Microbial Antigen Discovery (InMAD) to identify 5 candidate proteins. Specific Aim 1 will repeat this experiment and identify at least 5 additional candidate biomarkers (total of 10 proteins). Aim 2 will confirm at least 5 proteins as genuine biomarkers using IC serum samples from animal models and humans. If Phase I is successful, a Phase II application would i) generate monoclonal antibodies to biomarker proteins, ii) construct prototype immunoassays in LFI or ELISA format and iii) perform pre-clinical studies for diagnosis of IC.